Fluid handling



Sept. 13, L1966 J. T. KARBOSKY FLUID HANDL ING Filed Feb. 19, 1965United States Patent O 3,271,967 FLUID HANDLING Joseph T. Karbosky,Bartlesville, Okla., assignor to Phillips Petroleum Company, acorporation of Delaware Filed Feb. 19, 1965, Ser. No. 433,906 9 Claims.(Cl. 62-51) This invention relates to a method and apparatus forremoving a fluid from a source thereof. In one aspect this inventionrelates to a method and apparatus for coroling a iiuid, particularlybefore storage of that fluid.

Although this invention will, for the sake of brevity, be describedrelative to the treatment, storage and withdrawal of propane it is to benoted that the invention is broadly applicable to fiuids and inparticular liquids.

Propane is generally removed from very large storage facilities such asunderground Caverns and stored in smaller containers such as metal tanksbefore being introduced into the necessary transportation means such astanker ships, railroad cars, pipelines and the like. Heretofore problemshave been encountered in the loading of large transportation means suchas tanker ships in that large amounts of propane must be supplied in arelatively short time. Here the foremost problems encountered are thatthe iiow rate from the tank container must be decreased as that tankcontainer is gradually emptied to prevent collapse of the tank due tothe reduced pressure therein and that the refrigeration system employedto cool the propane before it is introduced into the tank container isgenerally of an inadequate capacity to handle the large amount ofpropane necessary to fill a tanker ship or similar large transportationmeans.

It has now been found that the rate of withdrawal of propane from a tankcontainer can be maintained substantially constant or even increasednotwithstanding high withdrawal rates if propane which is Warmer thanthat propane present in the tank container is introduced into the tankcontainer when the pressure therein falls below a predetermined minimumvalue necessary to maintain the desired rate of withdrawal of propanetherefrom.

The apparatus necessary for carrying out the above meth-od includes asupply conduit connected to a source of relatively Warm propane and avalved conduit connecting the supply conduit with a tank container fromwhich transportation means are to be loaded. The valve in the valvedconduit is operated by a means responsive to pressures prevailing in thetank container.

It has also been found that cooling of the propane prior to introductionof same into the tank lcontainer can be more effectively carried out ifthat propane is passed in heat exchange relationship through twoseparate heat exchangers, the first heat exchanger operating at apressure lower than the pressure of the refrigerant being suppliedthereto and the second heat exchanger operating at a pressure lower thanthe pressure of operation of the first heat exchanger. Thus, relativelywarm refrigerant can be passed into the first heat exchange zone and,due to the lower pressure and therefore lower boiling point of therefrigerant in that heat exchange zone, be cooled and be used to coolthe propane then passing through that heat exchange Zone. Liquidrefrigerant is then removed from the first heat exchange zone and passedinto the second heat exchange zone and, due to the lower pressure on therefrigerant in the second heat exchange zone, will be cooled further andtherefore cool the propane then passing through that heat exchange zone.Refrigerant vapors from both heat exchange zones are removed,compressed, cooled sufficiently to substantially liquefy same and thenreturned to the first heat exchange zone.

The apparatus for carrying out the above method in- ICC cludes first andsecond heat exchangers connected in series and interconnected with acompression and cooling means for forming liquefied refrigerant atelevated pressures. The refrigerant under high pressure is preferablyfirst passed through a receiver to allow for the settling out or otherremoval of impurities, such as compressor lubricant, prior tointroduction of same into the first heat exchanger.

Accordingly, it is an object of this invention to provide a new andimproved method and apparatus for removing a fluid from a sourcethereof. It is another object of this invention to provide a new andimproved method and apparatus of cooling a fluid, particularly beforethat uid is introduced into a storage zone.

Other aspects, objects and advantages of the invention will be readilyapparent to those skilled in the art from the description, the drawing,and the appended claims.

In the drawing there is shown diagrammatically a system embodying thisinvention.

More specifically, there is shown conduit 1 which contains a stream ofp-ropane from an underground cavern or similar storage zone which hasbeen treated as desired, e.g. dehydrated, and which must be cooledbefore being stored in a relatively smaller storage zone such as a tankcontainer. The propane flows through valved conduit 1 into heat exchangerelationship with heat exchanger 2 and from heat exchanger 2 throughvalved conduit 3 into heat exchange relationship with heat exchanger 4.From heat exchanger 4 the now sufciently cooled propane passes throughconduit 5 into tank container or storage tank 6. The ow of prop-anethrough conduit 5 is controlled by motor valve 7 which in turn iscontrolled through 8 by pressure controller 9. Pressure controller 9 isresponsive through 10 to the pressure in conduit 5 and through 11 and 12to the pressure in tank 6. Thus, if the pressure in tank 6 should fallbelow a preset minimum value pressure controller 9 would pinch downvalve 7 thereby at least slowing the flow of propane into tank 6 andopen valve 16 to allow warm liquid propane to flow therethrough. Undernormal conditions a predetermined pressure is maintained in line 5 fbyvalve 7 and valve 16 is closed.

Propane is removed from tank 6 through conduit 13 by pump 14 and passedto the waiting transportation or other storage means.

When the pressure in tank 6 falls below a preset minimum value due tothe rapid removal of propane through conduit 13 and pressure controller18 opens valve 16 thereby admitting relatively warm propane into tank 6,this relatively warm propane, in substantially liquid form, will flashsince it is generally pumped through conduit 1 at a substantially highertemperature than it is stored in tank 6 and at a pressure sufiicient tomaintain the propane at in the liquid state at said substantially highertemperature. The flashing of the warm propane increases the pressure intank 6 and, depending `on the amount of propane introduced through 15,can be used to maintain or increase the rate of withdrawal of propanethrough conduit 13.

Relatively warm propane from conduit 1 can also pass through conduit 20into receiver 21. The ow of propane through 20 is controlled by liquidlevel controller 22 on receiver 21 which through 23 controls motor valve24. Thus, if the liquid level in receiver 21 should fall below a presetminimum level, liquid level controller 22 will open valve 24 therebyadmitting more propane from 20. This propane is used in therefrigeration system for tank 6 and therefore acts as a refrigerant.

Receiver 21 is operated at a relatively high temperature and pressure ascompared to the temperatures and pressures in heat exchangers 2 and 4and the temperature and pressure in tank 6. The warm, high-pressure,refrigerant propane from receiver 21 passes through line 25 into heatexchanger 2. The rate of flow of refrigerant propane through 25 iscontrolled by liquid level controller 26 which through 27 controls motorvalve 28 in a manner similar to that described with refreence to liquidlevel controller 22. Heat exchanger 2 is maintained at a pressuresuflcient to cause the refrigerant propane to boil or vaporize at thedesired cooling temperature of that heat exchanger. Thus, some of therefrigerant propane in 25 flashes after passing through valve 28 and theboiling temperature of that propane in heat exchanger 2 is lowered duetothe lower pressure maintained in that heat exchanger. The pressure onthe refrigerant propane in heat exchanger 2 is of a magnitude such thatthe boiling temperature of that propane is lower than the temperature ofthe propanebeing passed in heat exchange relationship therewith byconduit 1. Since the boiling temperature of the refrigerant propane inheat exchanger 2 is lower than the temperature of the propane in conduit1 the propane in conduit 1 will be cooled.

Liquid refrigerant propane from heat exchanger 2 is removed by conduit30 and passed into heat exchanger 4. The rate of flow of refrigerantpropane through 30 is controlled by liquid level controller 31 whichthrough 32 controls motor valve 33 in a manner similar to that describedwith reference to liquid level control 22. Heat exchanger 4 ismaintained at an absolute pressure substantially below the pressuremaintained in heat exchanger 2, -i.e. no more than 40 percent,preferably from about 10 to about 35 percent, of the absolute pressurein heat exchanger 2.- Thus, liquid refrigerant propane in 30 ilas'hesafter passing through valve 33 and the pressure in heat exchanger 4V issuch that the -boiling temperature of the liquid refrigerant propanetherein is lower than the boiling temperature of the liquid refrigerantpropane in heat exchanger 2. Thus, the temperature of the refrigerantpropane in heat exchanger 4 is lower than both the temperature of therefrigerant propane in heat exchanger 2 and the temperature of thepropane passing from heat exchanger 2 through 3 into heat exchanger 4.Thus, cooled liquid propane passing from heat exchanger 2 throughconduit 3 is further cooled by heat exchanger 4 before being passedthrough S into tank 6.

Refrigerant propane vapors from heat exchanger 4 are removed therefromby 34 to scrubber 35. In scrubber 35 liquid material, such as compressoroil and liquid propane, is separated from the vapors and removed throughvalved line 36 to protect compressors 38 and 44 and for disposition asdesired. The vapors are removed from 35 through 37 to compressor 38which compressor sets the pressure in scrubber 35 and heat exchanger 4.The compressed vapor is passed from compressor 3S through 39 intoscrubber 40. Refrigerant propane vapors from heat exchanger 2 which areata higher pressure than the vapors from heat exchanger 4 pass from heatexchanger 2 through conduit 41 and conduit 39 into scrubber 40. Liquidsimilar to that found in 35 is separated from the vapors in scrubber 49and removed therefrom by valved line 42 for disposition as desired.Vapors are removed from scrubber 40 through conduit 43 into compressor44 wherein they are compressed and then passed by 4SV through heatexchanger 46. In 46 they are substantially completely condensed to theliquid state at their compressed (elevated) pressures. The liquidrefrigerant propane discharged from compressor 44 and after condensingin `46 is at a temperature and pressure substantially higher than theliquid refrigerant propane in heat exchanger 2. The compressed andsubstantially liquefied refrigerant propane passes from heat exchanger46 through 47 into receiver 21.

Propane vapors, which can contain substantial quantities of lowerboiling materials such as ethanes, formed in tank 6 pass therefromthrough conduit 5G, desuperheater spray -1 and into conduit 52.Normally, the vapors pass from 52 through conduit 53 into scrubber 54.The vapors can also pass through valved conduit 55. Normally closedmotor valve 56 in conduit 55 is controlled through 57 by pressurecontroller 58 which is responsive through 59 to pressures in tank 6.Thus, if the pressure in tank 6 should exceed a preset maximum valuepressure controller 58 will open valve 56 and allow propane vapors to beremoved through conduit 55 for a flare or other desired disposition.Liquid removed from the vapors in scrubber 54 pass through valved line62 into accumulator 63 and from 63 through valved conduits 64 and 65.The rate of ow of propane through 65 is controlled by motor valve 66which is controlled through 67 by pressure controller 68 which isresponsive through 69 to pressures in conduit 65. A preset pressure ismaintained upstream of valve 66. Thus, when the pressure upstream ofvalve 66 exceeds a preset maximum value pressure controller 68 willfurther open motor valve 66 thereby allowing more propane to flowtherethrough. Propane for the desuperheater spray 51 is supplied from 65through valved conduit 70.

Propane vapors from scrubber 54 pass through 71 to compressor 72 andfrom compressor 72 through 73 into heat exchange relationship with heatexchanger 4. The cooled propane then passes from heat exchanger 4through conduit 74 into cond-uit 65.

Compressed propane discharged from compressor 44 can be returned atleast in part through conduit to conduit 81 or conduit 82 or both. Theflow of propane from Sil through S1 to 34 is controlled by motor valve83 which is controlled through 84 by pressure controller 85 and which isresponsive through 86 to pressures in conduit 37 and scrubber 35. Thus,if the pressure in conduit 37 drops below a preset minimum valuenecessary for feeding compressor 38 or 44 pressure controller 85 willopen valve 83 thereby admitting heated propane discharged fromcompressor 44. If desired, hot propane discharged from compressor 44 can4be admitted by way of S2 into accumulator 63 and thereby, in effect,pass into tank 6. A similar compressor discharge return system can beemployed for compressor 72 between conduits '73 and 53 responsive topressure variation in tank 6.

Propane vapor from receiver 21 can pass through conduit 90 to 53 andinto scrubber 54. The flow of propane through 90 is controlled by motorvalve 91 which is controlled through 92 by pressure controller '93 whichis responsive through 94 to pressures in receiver 21. Thus, if thepressure in receiver 21 should exceed a preset maximum value pressurecontroller 93 will open motor valve 91 thereby allowing vapor to passinto 90.

Impurities in the propane in receiver 21 such as oil picked up fromcompressors 38 and 44 settle out and are removed from the system byvalved conduit 95.

If precleaning of the propane in 25 before introduction of same intoheat exchanger 2 is necessary, for example to remove additional oil orother impurities therefrom, a heat exchanger similar to heat exchanger 2can be employed in conduit 25 whereby refrigerant propane in line 25 iscooled by passing in heat exchange relationship with evaporating liquidrefrigerant propane supplied from heat exchanger 4. Oil or otherimpurities can be removed from the bottomcf this additional heatexchanger and the vapors formed therein can be combined with the vaporsflowing in conduit 34 for treatment in scrubber 35 and'compressor 3S. 7

Although the drawing has been described with the use of propane as arefrigerant in heat exchangers 2 and 4, it is to be noted thatrarefrigerant separate and distinct from the material ilowing throughconduits 1, 3 and 5 and being cooled by heat exchangers 2 and 4 can beemployed. It will be apparent that if a separate and distinctrefrigerant is employed conduits 20 and 82 can be omitted if desired.Also, in such a case conduit 9) would be disconnected from 53 andconnected to a separate vessel for collection of refrigerant :if anexcessive pressure requires the opening of motor valve 91.

Example Commercial propane passes through 1 at 90 F., 225 p.s.i.g. and182 gallons per minute. Tank 6 is maintained at 50 F. and from 3.5 to8.5 inches of water pressure. Tank 6 has a capacity of 180,000 barrelsof propane and no propane normally passes from 1 through 15 into tank 6.When tank 6 is being used to load a large transportation means such as atanker ship (which can require a load-ing rate of as much as 5,145gallons per minute) approximately 2,000 barrels per day of propane, 42volume percent of which fiashes to vapor after passing through valve 16,must be passed from 1 through 15 to maintain the pressure in tank 6.

The propane in 1 containing about 4 mol percent ethane passes into heatexchanger 2 at a temperature of 90 F. and leaves through 3 at atemperature of 31 F. The propane in 3 passes through heat exchanger 4and leaves therefrom at a temperature of 34 F. to pass through 5 intotank 6. The pressure of the liquid propane in 5 as it leaves heatexchanger 4 is 205 p.s.i.g.

Liquid propane at 90 yF. and 225 p.s.i.g. in 1 passes through 20 intoreceiver 21 which is maintained at 102 F. and 185 p.s.i.g. Relativelywarm, high pressure propane passes from receiver 21 through 25 to valve28 at a temperature of 102 F. and a pressure of 180 p.s.i.g. and at arate of 177 gallons per minute. The liquid propane upon passing throughvalve 28 ashes 29 volume percent of the liquid to vapor. Heat exchanger2 is maintained at a pressure of 40 p.s.i.g. which causes thetemperature of the propane therein to be maintained at 21 F. Liquidpropane leaves heat exchanger 2 through 30 at a temperature of 21 F. anda pressure of 40 p.s.i.g. at a rate of 86 gallons per minute and passesthrough valve 33 at which point 19.6 volume percent is flashed to vapor.Heat exchanger 4 is maintained at a pressure of about 14.7 p.s.i.a. or20 to 30 inches of water pressure and therefore a consequent temperatureof about 44 F. Propane vapors leave heat exchanger 4 through 34 at arate of 4,160,000 standard cubic feet per day at a temperature of 44 F.and a pressure of less than 0.1 p.s.i.g. Substantially the same amountof propane vapors leaves scrubber 35 through 37 and enter compressor 38.The propane is discharged from compressor 38 at a temperature of 70 F.and a pressure of 40 p.s.i.g. Propane vapors leave heat exchanger 2through 41 at a rate of 4,374,000 standard cubic feet per day at atemperature of 21 F. and a pressure of 40 p.s.i.g. The combined vaporsfrom 41 Iand compressor 38 are compressed in compressor 44 to -atemperature of 175 F. and a pressure of 190 p.s.i.g. These hot,compressed vapors pass through heat exchanger 46 and are cooled to 102F. and reduced to a pressure of 185 p.s.i.g. About 41,959 pounds perhour of propane passes through 47 into the receiver 21.

About 1,349,000 standard cubic feet per day of propane vapors containingabout 80 volume percent propane and about 20 volume percent ethane at 20F. and a pressure of less than 0.1 p.s.i.g. passes from tank 6 through53 into scrubber 54 which is maintained at 20 F. and 14.7 p.s.i.a.Substantially all of these vapors pass from 54 through 71 intocompressor 72 from which they are discharged at a temperature of 80 F.and a pressure of 35 p.s.i.g. They then pass through 73 into heatexchanger 4 and are removed therefrom as a liquid at a temperature of 34F. and a pressure of 30 p.s.i.g. for return to tank 6 through 74, 65 and5.

Reasonable variations and modifications are possible within the scope ofthis disclosure without departing from the spirit and scope of theinvention.

I claim:

1. A method for cooling a liquid comprising providing a source ofrefrigerant under an elevated pressure, passing said refrigerant into afirst heat exchange zone in which said refrigerant is maintained at alower pressure than `said refrigerant source to lower the boilingtemperature and therefore the temperature of the refrigerant in saidzone, passing said liquid in heat exchange relationship with saidrefrigerant in said first heat exchange zone to cool same, removingliquid refrigerant from said rst heat exchange zone and passing sameinto a second heat exchange zone in which said refrigerant is maintainedat a lower pressure than the pressure on said refrigerant in said firstheat exchange zone to further lower the boiling temperature andtherefore the temperature of same in said zone, removing said liquidfrom said first heat exchange zone and passing same in a heat exchangerelationship with said refrigerant in said second heat exchange zone tofurther cool said liquid, removing said Iliquid from said second heatexchange zone, removing refrigerant vapors from said second heatexchange zone and compressing same substantially to the pressuremaintained `in said first heat exchange zone, combining said compressedvapors from said second heat exchange zone with refrigerant vapors fromsaid first heat exchange zone, compressing said combined vapors andcooling same to form at least in part a refrigerant `liquid at atemperature and a pressure substantially the same as that of said sourceof refrigerant under elevated pressure, and introducing said compressedand cooled combined refrigerant vapors into said source.

2. A method according to claim 1 wherein the refrigerant in said sourceis passed through an additional heat exchange zone prior `to passingthrough said first heat exchange Zone to preclean said refrigerant bycollecting in said additional heat exchange zone liquified impurities,said `additional Iheat exchange zone being cooled by evaporation ofliquid refrigerant supplied from said second heat exchange zone.

3. A method for removing a fluid from `a first source thereof andcooling additional fluid being yintroduced into the same sourcecomprising withdrawing said fiuid from said source, introducing intosaid first source during said' withdrawal `at least part of saidadditional fiuid at a temperature and pressure higher than said fluid insaid first source when the pressure in said source drops be- Ilow apredetermined minimum value, providing a second source of refrigerantunder an elevated pressure, passing said refrigerant into a first heatexchange zone in which the refrigerant is maintained at a lower pressurethan said refrigerant source to lower the temperature of the refrigerantin said zone, passing at least part of said additional fluid in a heatexchange relationship with said refrigerant in said first heat exchangezone, removing said refrigerant from said first heat exchange zone andpassing same into a second heat exchange zone in which the refrigerantis maintained at a lower pressure than the refrigerant in said firstheat exchange zone -to further lower the temperature of saidrefrigerant, removing said additional fluid from said first heatexchange zone and passing same in a heat exchange relationship with saidrefrigerant in said second heat exchange zone, removing said refrigerantvapors from said first and second heat exchange zones, compressing andcooling said vapors to form at least in part a liquid refrigerant at atemperature and pressure substantially the same as said second source ofrefrigerant, and introducing said at least in part liquid into saidsecond source.

4. A method for removing a liquid from a first source thereof andprecooling additional liquid with liquid refrigerant of the same kindbefore introducing the additional liquid into the same source comprisingintroducing a first part of said additional liquid into said firstsource at a temperature and pressure higher than the liquid alreadypresent in said first source when the pressure in said source dropsbelow a `minimum value necessary to at least maintain the desired rateof withdrawal of liquid therefrom, passing a second part of saidadditional liquid into a separate second source of warm liquidrefrigerant under an elevated pressure, passing said liquid refrigerantfrom said second source into a first lheat exchange zone which ismaintained at a pressure lower than said liquid refrigerant in saidsecond source `to lower the boiling temperature .and therefore thetemperature of the refrigerant liquid in said first heat exchange Zone,passing a third part of said additional liquid in heat exchangerelationship with said liquid refrigerant in said first heat exchangezone, removing said -liquid refrigerant from said first heat exchangezone and passing same into a second heat exchange zone which ismaintained at a pressure loWer than the pressure on said refrigerant insaid first heatexchange zone to further lower the temperature of saidliquid refrigerant, removing the cooled third part of additional Iliquidfrom said first heat exchange zone and passing same in a heat exchangerelationship with the liquid refrigerant in said second heat exchangeZone to further cool said additional liquid, removing said furthercooled third part of additional -liquid from said second heat exchangezone into said first source, removing refrigerant vapors from saidsecond heat exchange zone and compressing same to a pressuresubstantially the same as the pressure maintained in said first heatexchange zone, removing refrigerant vapors from said first heat exchangeZone and lcombining same with the compressed refrigerant vapors fromsaid second heat exchange zone, compressing and cooling said cornbinedrefrigerant vapors to form a substantially liquid refrigerant `at atemperature and pressure substantially the same as the temperature andpressure of said second source of Warm liquid refrigerant under elevatedpressure, and introducing the compressed and cooled, substantiallyliquid refrigerant into said second source.

5. A method according to claim 4 wherein the sole liquid employed ispropane, the additional propane is at a temperature of 90 F. and apressure of 225 p.s.i.g., the first source is at a temperature of 50 F.and a pressure of less than 0.1 p.s.i.g., the second source is at atemperature of about 102 F. and a pressure of about 185 p.s.i.g., .thefirst heat exchanger is at a temperature of about 21 F. and a pressureof about 40 p.s.i.g., the second heat exchanger is at a temperature ofabout 44 F. and 'a pressure of less than 0.l p.s.i.g., the vapors fromthe second heat exchanger are compressed to a temperature of about 70 F.and a pressure of about 40 p.s.i.g., the combined vapors are compressedto a ternperature of about 175 F. and a pressure of about 190 p.s.i.g.,the combined vapors are cooled and returned to the second source at atemperature of about 102 F. and a pressure of about 185 p.s.i.g.

' 6. Apparatus for cooling a liquid comprising a storage containeradapted to hold a supply of Warm refrigerant liquid under an elevatedpressure, a first heat exchanger, a valved conduit openly connectingsaid container and said first heat exchanger, means for regulating theopening of the valve in said conduit responsive to liquid level in saidfirst heat exchanger, a second heat exchanger, a valved conduit openlyconnecting sai-d first heat exchanger and said second heat exchanger,means for regulating the opening of said valve in said con-duitresponsive to liquid level in said second heat exchanger, conduit meansfor passing a liquid to be cooled through said first heat exchanger andthen through said second heat exchanger, first compression means forcompressing refrigerant liquid vapors from said second heat exchanger,conduit means openly connecting said second heat exchanger with saidfirst compression means, second compression means for compressingrefrigerant liquid vapors from said first heat exchanger, conduit meansopenly connecting said first heat exchanger with said second compressionmeans, conduit means openly connecting said first compression means withsaid second compression means, means for cooling compressed refrigerantvapor discharged from said second compression means, conduit meansopenly connecting said second compression means and said cooling means,and conduit means openly connecting said cooling means and saidcontainer.

7. Apparatus for cooling a liquid comprising a first storage containeradapted to hold a supply of Warm refrigerant liquid under an elevatedpressure, a first heat exchanger, a first valved conduit openlyconnecting said first container and said first heat exchanger, means forregulating the opening of the valve in said conduit responsive to liquid-level in said first heat exchanger, a second heat exchanger, a secondvalved conduit openly communicating with said first valved conduit insaid first heat exchanger and said second heat exchanger, means forregula-ting the opening of said valve in said conduit responsive toliquid level in said second heat exchanger,

third conduit means for passing a liquid to be cooled through said firstheat exchanger and then through said second heat exchanger, first meansfor compressing refrigerant liquid vapors from said second heatexchanger, four-th conduit means openly communicating with said secondheat exchanger and said first compression means, second means forcompressing refrigerant liquid vapors from said first heat exchanger,fifth conduit means openly communicating With said first heat exchangerand said second compression means, sixth conduit means openly connectingsaid first compression means with said second compression means, meansfor cooling the compressed refrigerant vapor discharged from said secondcompression means, seventh conduit -means openly connecting said secondcompression and said cooling means, eighth conduit me-ans openlyconnecting said cooling means and said first container, `a secondcontainer, third means for compressing vapors from said secondcontainer, ninth conduit means connecting said second container and saidthird compression means, tenth conduit means for passing the dischargefrom said third compression means through said second heat exchanger andinto said second container.

S. Apparatus for removing a fiuid from a source thereof and for 4coolingthat fluid before introduction of same into said source comprising afirst container, a first conduit openly connected to said container forremoval of fluid therefrom, a second conduit for supplying warm liquidto be cooled and stored to the system, a third conduit openly connectingsaid second container and said first container, a valve operativelymounted in said -third conduit, means for opening said valve when thepressure in said first container drops below a predetermined minimumvalue, a second container for holding Warm liquid to be used asrefrigerant at an elevated pressure, a valved conduit openly connectingsaid second conduit and said second container, a first heat exchanger, avalved conduit openly connecting said Vsecond container and said firstheat exchanger, a second heat exchanger, a valved conduit openlyconnecting said first heat exchanger and said second heat exchanger,conduit means for'passing Warm liquid to be cooled from said secondconduit first through said first heat exchanger and then through saidsecond heat exchanger and finally into said first container, means forcompressing refrigerant vapors from said first and second heatexchangers, conduit means openly connecting said first and second heatexchangers with said cornpression means, means for cooling saidcompressed refrigerant vapors, conduit means openly connecting saidcompression means and said cooling means, and conduit means openlyconnecting said cooling means and said second container.

9. Apparatus for removing a liquid from a source thereof and forprecooling the same liquid prior to introduction of same into saidsource comprising a first storage container, a first conduit openlyconnected to said container .for removal of liquid therefrom, a secondconduit for supplying liquid to the system to be cooled and stored, athird conduit openly connecting said second conduit and said firststorage container, a normally closed motor valve operatively mounted insaid third conduit, pressure-sensing means operatively connected to theinferior 0f said first storage container and to said motor Valve andadapted to regulate the opening of said valve responsive to the pressurein said first storage container including opening said valve when thepressure in said first storage container drops below a preset minimumvalue, a second container for holding at an elevated pressure warmliquid to be used as refrigerant, a first valved conduit openlyconnecting said second conduit and said second container, means forregulating the opening of the valve in said first valved conduitresponsive to the liquid level in said second container, a first heatexchanger, a second valved conduit openly connecting said secondcontainer and said first heat exchanger, means for regulating theopening of the valve in said second valved conduit responsive to theliquid level in said first heat exchanger, a second heat exchanger, athird valved conduit openly connecting said first heat exchanger andsaid second heat exchanger, means for regulating the opening of thevalve in said third valved conduit responsive to the liquid level insaid second heat exchanger, conduit means for passing liquid to becooled from said second conduit through said first heat exchanger andthen through said second heat exchanger and finally into said firststorage container, first means for compressing refrigerant vapors fromsaid second heat exchanger, conduit means openly connecting said secondheat exchanger and said first compression means, second means forcompressing refrigerant vapors from said first heat exchanger, conduitmeans openly connecting said first heat exchanger and said secondcompressing means, conduit means openly connecting said firstcompression means and said second compression means, means for coolingcompressed refrigerant vapors, conduit means openly connecting saidsecond compression means and said cooling means, and conduit meansopenly connecting said cooling means and said second container.

References Cited by the Examiner UNITED STATES PATENTS 2,964,916 12/1960 Keeping 62-55 X 2,976,695 3/1961 Meade 62-55 X 3,058,314 10/1962Gardner 62-52 X 3,058,315 10/1962 Schuftan 62-53 X 3,106,827 10/ 1963Schlumberger 62-55 X 3,148,966 9/ 1964 Kitchen 62-21 3,163,992 1/1965Becker 62-55 3,191,395 6/1965 Maher et al, 62-52 X 3,195,316 7/1965Maher et al. 62-52 ROBERT A. OLEARY, Primary Examiner. LLOYD L. KING,Examiner.

1. A METHOD FOR COOLING A LIQUID COMPRISING PROVIDING A SOURCE OFREFRIGERANT UNDER AN ELEVATED PRESSURE, PASSING SAID REFRIGERANT INTO AFIRST HEAT EXCHANGE ZONE IN WHICH SAID REFRIGERANT IS MAINTAINED AT ALOWER PRESSURE THAN SAID REFRIGERANT SOURCE TO LOWER THE BOILINGTEMPERATURE AND THEREFORE THE TEMPERATURE OF THE REFRIGERANT IS SAIDZONE, PASSING SAID LIQUID IN HEAT EXCHANGE RELATIONSHIP WITH SAIDREFRIGERANT IN SAID FIRST HEAT EXCHANGE ZONE TO COOL SAME, REMOVINGLIQUID REFRIGERANT FROM SAID FIRST HEAT EXCHANGE ZONE AND PASSING SAMEINTO A SECOND HEAT EXCHANGE ZONE IN WHICH SAID REFRIGERANT IS MAINTAINEDAT A LOWER PRESSURE THAN THE PRESSURE ON SAID REFRIGERANT IN SAID FIRSTHEAT EXCHANGE ZONE TO FURTHER LOWER THE BOILING TEMPERATURE ANDTHEREFORE THE TEMPERATURE OF SAME IN SAID ZONE, REMOVING SAID LIQUIDFROM SAID FIRST HEAT EXCHANGE ZONE AND PASSING SAME IN A HEAT EXCHANGEZONE TO FURTHER COOL SAID LIQUID, REHEAT EXCHANGE ZONE TO FURTHER COOLSAID LIQUID, REMOVING SAID LIQUID FROM SAID SECOND HEAT EXCHANGE ZONE,REMOVING REFRIGERANT VAPORS FROM SAID SECOND HEAT EXCHANGE ZONE ANDCOMPRESSING SAME SUBSTANTIALLY TO THE PRESSURE MAINTAINED IN SAID FIRSTHEAT EXCHANGE ZONE, COMBINING SAID COMPRESSED VAPORS FROM SAID SECONDHEAT EXCHANGE ZONE WITH REFRIGERANT VAPORS FROM SAID FIRST HEAT EXCHANGEZONE, COMPRESSING SAIDDCOMBINED VAPORS AND COOLING SAME TO FORM AT LEASTIN PART A REFRIGERANT LIQUID AT A TEMPERATURE AND A PRESSURESUBSTANTIALLY THE SAME AS THAT OF SAID SOURCE OF REFRIGERANT UNDERELEVATED PRESSURE, AND INTRODUCING SAID COMPRESSED AND COOLED COMBINEDREFRIGERANT VAPORS INTO SAID SOURCE.